This study is a phase I, randomized, double-blind, placebo-controlled, dose escalation study. There will be 3 cohorts with 12 subjects in each cohort. Subjects will be randomized to receive thalidomide or matching placebo according to the following dose escalation schedule: Cohort 1 -- 50 mg thalidomide or matching placebo; cohort 2--150 mg thalidomide or matching placebo; cohort 3--300 mg thalidomide or matching placebo